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S. N. Dolya

Publications and source records attributed to S. N. Dolya.

29 records · Page 2Linked to original sources
arXiv2013

Linear_Accelerator_C+6_Ions_as_Injector_for_a_Synchrotron, Intended for Hadrons Therapy

We consider acceleration light ions by the field of a traveling-wave in a helical waveguide. The frequency of the accelerating RF field f = 100 MHz, generator power P = 2 MW. Ion focusing is provided by a solenoidal magnetic field with the intensity B = 3.5 Tesla. With increasing the accelerator length up to L = 15 m, the final energy of the ions can be increased up to a value of E = 7 MeV / nucleon.

physics.acc-ph↗
arXiv2011

Linear-circular proton accelerator with energy 0.8 GeV based on a rectangular cavity with E110 wave

We consider acceleration of protons in a cavity with such dimensions as length l = 10 m, width b = 20 m, height a = 1.01 m, located between two bending (180)degree magnets with isochronous magnetic field. The cavity is loaded with rows of drift plates (tubes), being excited by a wave of E110 type at the frequency fo = 148.5 MHz, excitation power P1 = 5.65 MW. Additionally, the cavity is fed with the power P2 = 8 MW, transmitted into a beam of protons with such parameters as the final energy 0.8 GeV, pulse beam current I = 10 mA, pulse width 25 microseconds, repetition rate 10 Hz. We discuss the possibility of creating a pulsed neutron source with the intensity In = 3e14 neutrons /s on the basis of such an accelerator.

physics.acc-ph↗
arXiv2009

Isothermal reentrant effect in a mesoscopic cylindrical structure of a superconductor coated with a normal metal layer

The coherent phenomena in mesoscopic cylindrical normal metal (N) - superconductor (S) structures have been investigated theoretically. The magnetic moment (persistent current) of such a structure has been calculated numerically and (approximately) analytically. It is shown that the current in the N layer corresponding to the free-energy minimum is always diamagnetic. As the field increases, the magnetic moment (current) exhibits jumps at certain values of the trapped magnetic flux and the NS structure changes to a state with smaller absolute value of the diamagnetic moment. This occurs when the persistent current is unable to screen the external field. The magnetic moment increase stepwise and the system changes into a new stable state. The magnetic field penetrates into a larger volume of the N layer. The state has smaller absolute value of the diamagnetic moment. Experimentally, this is interpreted as the presence of a paramagnetic addition in the system (paramagnetic reentrant effect). The results obtained are in qualitative agreement with the experiments conducted by P. Visani et al. [Phys. Rev. Lett. 65, 1514 (1990)].

cond-mat.supr-con↗
arXiv2009

About the Electrodynamic Acceleration of Macroscopic Particles

An electric charge is imparted to macroscopic particles, whereupon they are pre-accelerated in an electrostatic field by the high voltage U = 220 kV. Then the particles are accelerated by a traveling electromagnetic wave with the initial phase velocity lying in the range v/c = 1e-3 - 1e-5. Focusing the particles is provided by electrostatic doublets. At the acceleration length L = 20 m, the particles with Z/A = 2.3e-7 increase their velocity from v/c = 1e-5 to v/c = 1e-4.

physics.acc-ph↗
arXiv2009

An Intensive Pulsed Neutron Source Based On An Electron Ring Accelerator

A neutron source is proposed. It is based on a proton accelerator with the energy Ep = 1.2 GeV, current Ip = 0.7A, pulse duration T = 3 mcsec, repetition rate F = 60 Hz, and accelerator length L = 30 m. Protons are accelerated by the field of electron rings. The electron rings are formed from a tube beam by way of modulation and creating rotating motion by crossing the magnetic field cusp. The frequency of modulation f1 = 142.8 MHz. The bunch is accelerated at the frequency f3 = 2856 MHz. The high frequency power required for making the field is P1 = 6 - 150 MW/section, the power transferred to the accelerated beam is P2 = 75 - 100 MW/m. The bigger radius of the rings (r0 = 2 cm) and radial dimensions of the ring (ar = 0.125 cm) are provided by the external magnetic field B0 = 2.4 T. The longitudinal dimensions (az < 0.22 cm) are maintained by the wave moving synchronously with the bunches. The number of electrons in each ring Ne = 3e12, the number of protons Np = 3e10. Protons are accelerated at the constant energy gain rate 40 MeV/m. The electron rings are accelerated in the waveguide with the field strength Ez = 1.08 MV/m. The intensity of the proton beam is 1e13 p/pulse. The average intensity of the neutron flux on a lead target is Ian = 1e16 n/s, the pulsed neutron flux is Ipn = 8e19 n/s.

physics.acc-ph↗
arXiv2008

Quasi-exactly solvable models based on special functions

We suggest a systematic method of extension of quasi-exactly solvable (QES) systems. We construct finite-dimensional subspaces on the basis of special functions (hypergeometric, Airy, Bessel ones) invariant with respect to the action of differential operators of the second order with polynomial coefficients. As a example of physical applications, we show that the known two-photon Rabi Hamiltonian becomes quasi-exactly solvable at certain values of parameters when it can be expressed in terms of corresponding QES operators related to the hypergeometric function.

math-ph↗
arXiv2001

Quasi-exactly solvable quartic Bose Hamiltonians

We consider Hamiltonians, which are even polynomials of the forth order with the respect to Bose operators. We find subspaces, preserved by the action of Hamiltonian These subspaces, being finite-dimensional, include, nonetheless, states with an \QTR{it}{infinite} number of quasi-particles, corresponding to the original Bose operators. The basis functions look rather simple in the coherent state representation and are expressed in terms of the degenerate hypergeometric function with respect to the complex variable labeling the representation. In some particular degenerate cases they turn (up to the power factor) into the trigonometric or hyperbolic functions, Bessel functions or combinations of the exponent and Hermit polynomials. We find explicitly the relationship between coefficients at different powers of Bose operators that ensure quasi-exact solvability of Hamiltonian.

quant-ph↗
arXiv2001

General approach to potentials with two known levels

We present the general form of potentials with two given energy levels $E_{1}$, $E_{2}$ and find corresponding wave functions. These entities are expressed in terms of one function $ξ(x)$ and one parameter $ΔE=E_{2}$-$E_{1}$. We show how the quantum numbers of both levels depend on properties of the function $ξ(x)$. Our approach does not need resorting to the technique of supersymmetric (SUSY) quantum mechanics but automatically generates both the potential and superpotential.

quant-ph↗
arXiv2000

Quantum anharmonic oscillator and quasi-exactly solvable Bose systems

We extend the notion of quasi-exactly solvable (QES) models from potential ones and differential equations to Bose systems. We obtain conditions under which algebraization of the part of the spectrum occurs. In some particular cases simple exact expressions for several energy levels of an anharmonic Bose oscillator are obtained explicitly. The corresponding results do not exploit perturbation theory and include strong coupling regime. A generic Hamiltonian under discussion cannot, in contrast to QES potential models, be expressed as a polynomial in generators of $sl_{2}$ algebra. The suggested approach is extendable to many-particle Bose systems with interaction.

quant-ph↗
arXiv2000

Linac Lue200. First Testing Results

"LUE200" - 200 MeV electron linac is being created at JINR as a driver of the pulsed neutron source "IREN" [1]. The special full-scale facilities for testing the main systems of LUE-200 (FSTF) are used at JINR, BINP, MEPhI and YerPhI [2]. The verification of the linac accelerating system is providing at the VEPP-5 preinjector constructed at BINP [3]. The accelerating system of LUE200 includes two S-band (2856 MHz) accelerating sections of 3 m long. The sections are connected with modulator based one 5045 klystron (SLAC production). There are SLED-systems for the multiplying the pulse RF power. The first results of the accelerating system test on the VEPP-5 preinjector are presented. The electron beam energy up to 92 MeV and consequently average rate of acceleration of the electron beam more than 30 MeV/m were achieved after acceleration in one section.

physics.acc-ph↗